Ciprofloxacin Coverage of Staphylococcus saprophyticus
Yes, ciprofloxacin is highly effective against Staphylococcus saprophyticus and is an appropriate treatment choice for infections caused by this organism. 1
Microbiological Activity
Ciprofloxacin demonstrates excellent in vitro activity against S. saprophyticus, which is explicitly listed as a susceptible organism in the FDA drug label 1. The fluoroquinolone class, including ciprofloxacin, exerts bactericidal action by inhibiting DNA gyrase and topoisomerase IV, which are essential for bacterial DNA replication 1.
Clinical Evidence Supporting Use
Multiple studies confirm ciprofloxacin's effectiveness:
- All S. saprophyticus isolates tested in a French surveillance study (2007-2009) were susceptible to ciprofloxacin 2
- A case report documented successful treatment of S. saprophyticus bacteremia originating from urinary tract infection using intravenous ciprofloxacin 3
- Historical susceptibility data from 1982 showed universal susceptibility of S. saprophyticus to fluoroquinolones, though this predated ciprofloxacin's widespread use 4
Practical Considerations
For urinary tract infections caused by S. saprophyticus:
- Ciprofloxacin is appropriate for both uncomplicated cystitis and pyelonephritis 2, 3
- Standard dosing is 250-500 mg orally twice daily for uncomplicated UTI 1
- For more severe infections or bacteremia, 750 mg orally twice daily or intravenous administration may be warranted 3, 5
Important caveats:
- S. saprophyticus is naturally resistant to nalidixic acid and novobiocin, but this does not affect ciprofloxacin susceptibility 4
- While ciprofloxacin has excellent activity against S. saprophyticus, it has relatively poor activity against S. pneumoniae compared to newer fluoroquinolones (levofloxacin, moxifloxacin) 6
- Avoid concurrent administration with antacids containing magnesium or aluminum, which can reduce bioavailability by up to 90% 1
Resistance Monitoring
Resistance to ciprofloxacin among S. saprophyticus remains rare, with surveillance data showing maintained susceptibility 2. However, resistance can develop through multiple-step mutations when fluoroquinolones are used 1, making culture and susceptibility testing important for treatment failures.